Percussion fuze for rocket



Jan. 21, 1964 v J. R. JASSE 3,118,378

, PERCUSSION FUZE FOR ROCKET 7 Filed Dec. 14, 1961 2 Sheets-Sheet 1 Jan. 21, 1964 J R JASSE I 3,118,378

PERCUSSION FUZE FOR ROCKET Filed Dec. 14, 1961 2 Sheets-Sheet 2 United States Patent rate Filed Dec. 14, 196i, Ser. No. 159,395 Claims priority, application France Dec. 19, 1960 2 Claims. (Cl. 102-48) The present invention relates to percussion fuzes for rockets or the like.

Known percussion fuzes are generally armed while the rocket travels through the launching tube so that should the rocket become wedged in this tube it is necessary to handle the rocket with its fuze armed. Fuzes exist which are safe to launch, the means providing this safety being in the form of a pin which is ejected at the moment when the rocket issues from the launching tube and determines the arming of the fuze. But this solution has grave disadvantages, and in particular it is very complex in construction, lacks fiuidtightness and is excessively large since the pin extends up to the face of the inner wall of the launching tube so that the latter prevents a premature ejection of the pin.

The object of the invention is to provide an improved completely safe percussion fuse for a rocket which avoids all these disadvantages.

The fuze according to the invention is simple in construction, operates faultlessly, and is of the type having a percussion pin locked in its position of rest by a locking device controlled by an arming element which is moved by inertia in opposition to the action of elastically yieldable means between an inoperative position in which the locking device locks the pin and an arming position in which the pin is released.

The fuze is so arranged that the arming element is adapted to form a percussion mass adapted to strike the percussion pin on impact.

Preferably, the arming element constitutes, in combination with its housing in the body of the fuze, an air braking device or dashpot so that in the event of the rocket becoming wedged in the launching tube the fuze is not armed.

The fuze further comprises means which afford total safety and are operated by the breaking of the pyrotechnic chain or train, the fuze comprising in the known manner a detonator carrier pivotable between an inoperative position of rest in which it is maintained by the percussion pin, which is also in its position of rest, and an operative position toward which it is urged by an elastically yieldable device after retraction of the percussion pin at the end of the arming of the fuze.

Further features and advantages of the invention will be apparent from the ensuing description, with reference to the accompanying drawings to which the invention is in no way limited.

In the drawings:

FIG. 1 is a half-longitudinal sectional view and a halfelevational view of a fuze according to the invention in its normal unarmed condition;

FIG. 2 is a corresponding sectional view taken along line 2-2 of FIG. 1;

FIG. 3 is a partial side view of the percussion pin carrier;

FIG. 4 is a view similar to FIG. 1 but in which the various elements of the fuze are shown in the positions they assume while the fuze undergoes positive acceleration on its trajectory;

FIG. 5 is a view similar to been armed, and

FIG. 6 is a sectional view taken along line 6-6 of FIG. 5.

FIG. 4, the fuze having 3,ll8,378 Patented Jan. 21, 1964 "ice In the illustrated embodiment, the fuze comprises a body having two parts or elements It and 2 interconnected by screwtln'eading at 3. The screwthreading of part 2 also permits the screwthreaded mounting of the fuze in the nose end of the rocket R (FIG. 1). Two annular ribs 4 and 5 formed on the parts I and 2 define therein three cylindrical cavities 6, '7, 8 which communicate with one another by way of apertures 9 and ill (FIG. 1).

The forward cavity 6 contains a percussion and arm ing device. It comprises a fixed tubular guide 11 screwed in the aperture 9 which is tapped for this purpose. Slidable in the guide 11 along the longitudinal axis X-X of the fuze is a percussion element comprising a percussion pin 12 having a rear pointed end 13 and a forwar head 14 on which is riveted a percussion pin carrier 15 which is axially movable along the outer face of the guide 11. This percussion pin carrier consists of a cylindrical sleeve having, on the one hand, apertures 16 adapted to act at rest (FIG. 1) as housings for locking balls 17 in combination with a recess 18 formed in the outer face of the guide 11 and, on the other hand, a zig-zag groove 19 (FIGS. 1 and 3) whose function will be explained hereinafter and which terminates at its lower end in a recess 2%. It will .be understood that this zig-zag groove has such angular position relative to the axis X-X as not to be intersected by one of the apertures 16.

Axially slidable on the carrier 15 is an arming element consisting of a piston 21 having a rearwardly open blind hole 22 so that this piston has a cylindrical skirt adapted to slide on the carrier 15 and a solid forward transverse wall 23. Provided in the hole 22 is a recess 2 3 having such longitudinal position that at rest (FIG. 1) it is forwardly offset relative to the apertures 16 of the carrier 15.

The arming piston 21 is slidably mounted by the cylindrical outer face of its skirt in the cylindrical face of the cavity 6 of the body of the fuze with a very small clearance so that this piston forms in combination with the face 6 an air brake device or dash-pot, the air being capable of passing only slowly through this clearance from the forward chamber A to the rear chamber B provided in the fuze body on either side of the piston.

It will be observed that this piston, which moreover constitutes a percussion mass as will be explained hereinafter, is, on the one hand, urged forwardly by a spring 24a located between the piston and the rib 4 and, on the other hand, provided with a pin whose inner end projects into the blind hole 22 and engages the zigzag groove 19 of the percussion pin carrier 15 (FIGS. 1 and 2).

The forward chamber A is closed by a cap 26 over which the forward end of part 1 is riveted at 27.

Disposed in the intermediate cavity '7 is a support 23 which is pivotally mounted on a pivot 29 having an axis Y-Y which is eccentric relative to the axis XX (FIGS. 2 and 5). This support carries a detonator primer Zill and it is urged by a spring 31 to pivot about the axis Y-Y in the direction of arrow it (FIG. 2) from the position of rest shown in FIGS. 1, 2 and 4, in which the primer 3%? is laterally offset from the axis X-X, to the operative position shown in FIGS. 5 and 6 in which this primer is centered on the axis XX. The detonator carrier 28 is held in the position of rest by the rear end of the percussion pin I2 which is engaged in an aperture 32 formed in this carrier 28.

The rear cavity a contains a booster 33 whose charge 34 is adapted to be ignited by the detonator primer 3h.

The fuze operates in the following manner:

At rest (FIG. 1), the pin 12 is locked, through the medium of the percussion pin carrier 15, by the balls 17 which are trapped in their apertures 16 by the arming piston 21. The detonator carrier 28 is held stationary 3 by the pin 12 in the inoperative retracted position shown in FIG. 2 so that the pyrotechnic chain comprising the pin 12, the primer 39 and the booster 33 is broken in the primer part thereof.

The arming piston 21 is protected by the cap 26 which is of plastic material and which renders the fuze fluidtight.

Upon launching the rocket at the moment the propelling means for the rocket start to operate, under the effect of the positive acceleration imparted to the rocket, the piston 21 is rearwardly displaced by inertia and compresses the spring 24a.

During this axial displacement of the piston 21, the pin 25 engaged in the Zig-zag groove 19 (FIGS. 3 and 4) constrains the piston to effect an oscillatory movement relative to the carrier while said axial displacement is delayed by the action of the dash-pot formed thereby; in the chamber A, which increases in volume, a partial vacuum is created which retards the displacement of the piston since the air must pass from the rear chamber B to the forward chamber A, via the small radial clearance between the piston 21 and the inner face 6 of the fuse body.

At the end of the rearward travel of the piston the pin 25 reaches the recess (FIG. 3) of the zig-zag groove and this locks the piston relative to the percussion pin carrier 15, while the recess 24 of the piston is in alignment with the balls 17. The latter enter the recess 24 and this releases them from the apertures 16 and the recess 13 and thus unlocks the percussion pin. These elements are then in the position shown in FIG. 4 and remain in these positions as long as the fuze undergoes a positive acceleration. As soon as this positive acceleration ceases, the spring 24:: returns the piston 21 to its initial position. Owing to the engagement of the pin 25 in the recess 25) in the carrier 15, the latter and consequently the percussion pin 12 rigid therewith are driven forwardly by the piston from the position shown in FIG. 4 to that shown in FIG. 5 which causes the detonator carrier 23 to be unlocked. Under the effect of the spring 31 the detonator carrier pivots about the axis YY and assumes the operative position shown in FIGS. 5 and 6. The fuze is armed.

Gn impact with the target or other object the plastic cap 26 is crushed and the piston 23, which then forms a striking mass, forces the percussion pin 22 into the detonator primer 36).

Although a specific embodiment of the invention has been described, many modifications and changes may be made therein without departing from the scope of the invention as defined in the appended claims.

Having now described my invention what I claim as ew and desire to secure by letters patent is:

1. In a percussion fuze for a rocket of the type in which a percussion element is adapted to strike, upon impact of the fuze a ainst an exterior object, a primer located rearwardly of the percussion element, the structure comprising a fuze body having a longitudinal axis and, in said body: an internal forward cylindrical cavity, a tubular guide rigid with and coaxial with the body in the cavity, a percussion pin, a percussion pin carrier rigid with the percussion pin and slidaoly mounted on the guide so that the percussion pin is movable on said axis between a near position and a forward armed position, an arming element in the form of a hollow piston coaxial with the percussion pin and having a closed forward end portion located forward of the carrier and a skirt portion which encompasses the carrier and is slidably mounted in the cavity so as to divide the cavity into a forward fluidtight chamber forward of the piston and a rear chamber, a slight radial clearance being provided between the piston and cavity to allow air to slowly pass from the rear chamber to the forward chamber when the piston moves rearwardly of the body thereby slowing down said rearward movement, means for locking the percussion pin in said rear position and comp ising a tiroughway aperture in the carrier, a first recess in the guide and a locking ball disposed in the aperture and recess when the percussion pin is in said rear position, elastically yieldable means interposed between the piston and the body and biasing the piston toward a forward position when the fuze is not accelerating, the skirt extending across said aperture and preventing the ball from escaping from the aperture in said forward position of the piston and having a second recess in the skirt which, when the fuze accelerates and the piston moves rearwardly of the body to a rear position under the effect of inertia and in opposition to the action of the elastically yieldable means, comes into alignment with said aperture and allows the ball to move completely into the second recess and retract from the first recess and thereby release the percussion pin, hooking means comprising an element carried by the piston and an element provided on the carrier said elements hookingly engaging each other in said rear position of the piston so that, when the fuze decelerates and the elastically yieldable means urge the piston to said forward position thereof, the percussion pin is driven by the piston through the medium of the carrier to said armed position, the piston being capable of moving rearwardly of the carrier and striking the carrier when the percussion pin and piston are in said armed and forward positions respectively.

2. Fuze as claimed in claim 1, comprising a primer carrier movably mounted in the body at the rear of the percussion pin, a primer carried by the primer carrier, and a spring for urging the primer carrier from a first position in which the primer is laterally retracted relative to the percussion pin and a percussion position in which the primer is located on the extension of the axis of the percussion pin, the percussion pin having such length that in said rear position thereof it lockingly engages the primer carrier so as to maintain the latter in said first position in opposition to the action of said spring, whereas when the percussion pin moves forwardl to said armed position the percussion pin is disengaged from the primer carrier and permits the latter to move under the action of the spring to said percussion position.

References Qited in the file of this patent UNITED STATES PATENTS 

1. IN A PERCUSSION FUZE FOR A ROCKET OF THE TYPE IN WHICH A PERCUSSION ELEMENT IS ADAPTED TO STRIKE, UPON IMPACT OF THE FUZE AGAINST AN EXTERIOR OBJECT, A PRIMER LOCATED REARWARDLY OF THE PERCUSSION ELEMENT, THE STRUCTURE COMPRISING A FUZE BODY HAVING A LONGITUDINAL AXIS AND, IN SAID BODY: AN INTERNAL FORWARD CYLINDRICAL CAVITY, A TUBULAR GUIDE RIGID WITH AND COAXIAL WITH THE BODY IN THE CAVITY, A PERCUSSION PIN, A PERCUSSION PIN CARRIER RIGID WITH THE PERCUSSION PIN AND SLIDABLY MOUNTED ON THE GUIDE SO THAT THE PERCUSSION PIN IS MOVABLE ON SAID AXIS BETWEEN A NEAR POSITION AND A FORWARD ARMED POSITION, AN ARMING ELEMENT IN THE FORM OF A HOLLOW PISTON COAXIAL WITH THE PERCUSSION PIN AND HAVING A CLOSED FORWARD END PORTION LOCATED FORWARD OF THE CARRIER AND A SKIRT PORTION WHICH ENCOMPASSES THE CARRIER AND IS SLIDABLY MOUNTED IN THE CAVITY SO AS TO DIVIDE THE CAVITY INTO A FORWARD FLUIDTIGHT CHAMBER FORWARD OF THE PISTON AND A REAR CHAMBER, A SLIGHT RADIAL CLEARANCE BEING PROVIDED BETWEEN THE PISTON AND CAVITY TO ALLOW AIR TO SLOWLY PASS FROM THE REAR CHAMBER TO THE FORWARD CHAMBER WHEN THE PISTON MOVES REARWARDLY OF THE BODY THEREBY SLOWING DOWN SAID REARWARD MOVEMENT, MEANS FOR LOCKING THE PERCUSSION PIN IN SAID REAR POSITION AND COMPRISING A THROUGHWAY APERTURE IN THE CARRIER, A FIRST RECESS IN THE GUIDE AND A LOCKING BALL DISPOSED IN THE APERTURE AND RECESS WHEN THE PERCUSSION PIN IS IN SAID REAR POSI- 